diff --git a/mk/spdk.common.mk b/mk/spdk.common.mk
index 26690ac9d7..4ddfd327c9 100644
--- a/mk/spdk.common.mk
+++ b/mk/spdk.common.mk
@@ -58,6 +58,8 @@ ifeq ($(CONFIG_DEBUG), y)
 COMMON_CFLAGS += -DDEBUG -O0
 else
 COMMON_CFLAGS += -DNDEBUG -O2
+# Enable _FORTIFY_SOURCE checks - these only work when optimizations are enabled.
+COMMON_CFLAGS += -D_FORTIFY_SOURCE=2
 endif
 
 CFLAGS   += $(COMMON_CFLAGS) -Wno-pointer-sign -std=gnu11